Repair doubler patches may be used to repair composite materials in a variety of applications. In the aircraft industry, for example, repair doubler patches may be used to repair an area of a composite material fuselage, wing skin panel or other composite structure. The repair doubler patch may be applied to the repair area on the composite structure with an adhesive using heat and pressure to cure the adhesive and form a strong bond between the patch and the structure.
Current pre-cured composite repair doubler patches which bond to composite structures may utilize either chemical heat packs or electrical heat blankets. Chemical heat packs may require little or no technical training for operation and no electrical power source. However, chemical heat packs may have a limited upper temperature (such as 120 degrees F.) and duration at desired temperature (such as less than 30 minutes). Heat blankets may be more reliable than chemical heat packs in holding temperature and reaching higher temperatures but require a control system which is operated by a skilled technician as well as an electrical source for operation. Both chemical heat packs and heat blankets may generate thermal heat from the exterior portion of the repair with no guarantee that the heat is being distributed evenly and thoroughly. Thermal couples may be used to monitor temperature but are only capable of recording temperature at a single point. Chemical heat packs and heat blankets may not provide any compaction capability. Consequently, heating may not be localized to the adhesive bondline of the repair doubler patch.
For composite bonded repairs, even heat distribution across the adhesive bondline area of the repair may be desirable. Even and accurate adhesive heating for the curing process may be necessary to meet desired structural properties of the adhesive material used to effect the repair.
Accordingly, a doubler repair apparatus and method are needed for the repair curing process to meet desired structural properties of the adhesive material in a repair.